1. Field of the Invention
This invention relates to a device for retrieving pipeline pigs.
2. Discussion of the Prior Art
A pig is a device which is caused to flow through fluid hydrocarbon conveying pipe lines or conduits as an aid for removing undesired deposits which form on the inside surfaces of the pipe or conduit. Pigs may also be employed as markers. For example a pig may be inserted between separate charges of different fluids to indicate the end of a specific charge and the beginning of another charge. Pigs take the form of shperiods or plugs or torpedo type configurations which have diameters slightly smaller than the inner diameter of the pipes or conduits. Pigs may be constructed of a variety of materials such as resilient foam, rubber, or metals such as stainless steel or aluminum.
There are known devices which allow an operator to retrieve pigs. Such devices include a pig receiver and relatively large structures of cooperating parts to extract the pigs through an opening of the receiver. Such structures are disclosed in U.S. Pat. Nos. 3,232,090 and 3,809,113.